1. A disciplinary measure for children whereby the child is striken on the bottocks, either bared or clothed, with either the hand or an implement such as a wooden spoon.
2. A fetish were but consenting adults strike each other on the butt to induce sexual pleasure.

A sexual fetish act where a submissive woman's ass is playfully tanned by a dominant man for both their pleasure. However, if both the man and the woman aren't consenting adults, it becomes ABUSE and is ILLEGAL

Spanking can either be bare handed or with a spanking implement like a hairbrush

Spanking can either be over the knee or on a spanking horse. It can also be used as a non-sexual disciplinary measure.